1. Field of the Invention
This invention relates generally to umbrellas for shading people from the sun or the elements. More specifically, the invention relates to umbrellas that may be used on river rafts and boats, on other vehicles, and in other recreational settings. The invention relates specifically to an umbrella system that can be quickly set-up or taken down, quickly adjusted, and that is lightweight and easily-operated during travel on a raft or other moving equipment.
2. Related Art
There are many umbrellas for shading people and areas, such as cafe umbrellas and personal umbrellas. Conventionally, these umbrellas fall into the two main categories depending on how the umbrella is supported.
The first category is the umbrella that is supported from below, by a centrally-located pole at the axis of the umbrella fabric shade portion, such as in a conventional hand-held umbrella or patio table umbrella. In this first category, the space underneath the umbrella is limited, because the support pole takes up space and obstructs movement underneath the umbrella.
The second category is the umbrella that is suspended from above, typically by an arm on a support pole that reaches over the umbrella shade portion and connects to the center of the shade portion. Examples of the second category of umbrellas are found in the patent literature, including Xu (U.S. Pat. No. 6,196,242 issued Mar. 6, 2001); Tung (U.S. Pat. No. 6,152,156 issued Nov. 28, 2000); Steiner (U.S. Pat. No. 5,960,806 issued Oct. 5, 1999); Koehn (U.S. Pat. No. 5,845,665 issued Dec. 8, 1998); Glatz (U.S. Pat. No. 5,785,069 issued Jul. 28, 1998); Vennik (U.S. Pat. No. 5,116,258 issued May 26, 1992); Glatz, et al. (U.S. Pat. No. 4,586,525 issued May 6, 1986). These umbrellas include complex opening and closing systems, including cables, cranks, locks, hinges and pivots. The shade and support structure of such umbrellas are typically complex, heavy, and difficult to operate, because the cable extends typically from the lower central axis of the umbrella shade portion, through the umbrella axis, suspension arm and all the way to the lower end of the support pole, and because a crank and lock mechanism is needed to control movement of the cable. Consequently, these complex umbrellas are not very portable or quickly-operated, so that they are used in situations in which the umbrella is stationary, on a patio or street, and does not need to be moved or frequently opened or closed.
Several umbrellas use complex pivot arm and boom systems, such as Glatz (U.S. Pat. No. 6,220,261 issued Apr. 24, 2001); Geniele (U.S. Pat. No. 5,499,644 issued Mar. 19, 1996); May (U.S. Pat. No. 5,678,585 issued Oct. 21, 1997; and Collet (U.S. Pat. No. 4,606,366 issued Aug. 19, 1986). Like the cable-operated umbrellas, these umbrellas are complex, and tend to be heavy and difficult to operate.